• NextEnergy UK I has acquired three operational battery storage projects in southeast England with a combined capacity of 107 MW.
• The deal lifts the fund’s standalone battery capacity to 165 MW and adds operational, cash-generating assets backed by long-term Capacity Market contracts.
• The $991 million fund has built and acquired more than 1 GW of UK renewable energy infrastructure since launching in 2021.

NextEnergy Capital has expanded its UK battery storage portfolio with the acquisition of 107 MW of operational assets in southeast England.

The portfolio was acquired through NextEnergy UK I the private fund managed by the UK renewables investor. It comprises three standalone battery energy storage systems located near major electricity demand centres.

The assets include the 40 MW Maldon battery, 28 MW Basildon facility and 39 MW Loudwater project. All three have long-term Capacity Market contracts and established routes to market with operational counterparties.

Financial terms of the transaction were not disclosed.

Operational batteries add immediate revenue

The acquisition takes NEUK I’s standalone battery storage capacity to 165 MW. It also adds operating assets that can generate revenue immediately.

That distinction matters as investors assess the risk profile of energy storage. Operational projects remove much of the development and construction risk associated with greenfield infrastructure.

Long-term Capacity Market contracts can also provide an element of contracted revenue. The UK mechanism pays capacity providers to ensure electricity is available when the system needs it.

The batteries are positioned close to electricity demand centres and grid infrastructure in southeast England. This allows them to provide flexibility as renewable generation expands across the UK power system.

Battery storage can absorb excess electricity when supply is high and return power when demand increases. Its role is becoming more important as intermittent wind and solar generation account for a greater share of electricity supply.

Portfolio previously owned by Eku Energy

The three assets were previously owned by Eku Energy, the battery storage platform launched by Macquarie’s Green Investment Group.

Eku Energy commissioned the Maldon BESS in September 2024. The Loudwater and Basildon facilities were energised in early 2025.

Their addition gives NEUK I greater exposure to energy storage alongside its existing utility-scale solar investments.

“This acquisition represents an important milestone for NEUK I, further advancing the fund’s investment strategy through the addition of high-quality operational BESS assets that complement its existing solar and storage investments. The acquired portfolio further diversifies cash flows for our investors and strengthens NEUK I’s exposure to the rapidly growing energy storage sector,” said Ross Grier, chief investment officer at NextEnergy Capital.

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$991 Million fund expands beyond solar

NEUK I reached final close with $991 million in commitments. The ten-year closed-end fund had initially targeted £500 million.

Since launching in 2021, it has built and acquired more than 1 GW of renewable energy infrastructure across the UK.

Its strategy centres on UK solar projects supported by power purchase agreements, alongside selected battery storage investments. Adding operational batteries broadens that model by introducing assets with different revenue streams and operating profiles.

For institutional investors, that diversification is increasingly relevant. Renewable infrastructure portfolios must manage exposure to power prices, grid constraints and changing generation patterns.

Storage can help address those risks while creating additional revenue opportunities through capacity and electricity markets.

Storage becomes central to UK power strategy

The transaction comes as Britain increases its reliance on renewable electricity and seeks greater flexibility across its power system.

That creates a growing role for private capital. Grid-scale batteries require significant investment, while investors must navigate merchant power exposure, grid connections and evolving market rules.

Operational assets with existing contracts can offer a different risk profile from projects still awaiting construction or connection.

For NextEnergy, the acquisition also extends its strategy beyond renewable generation alone. Solar produces electricity, while batteries can help determine when that electricity is most valuable to the wider system.

As renewable penetration rises, that combination is becoming increasingly important. The UK market provides a test of how institutional capital can pair generation with flexibility while pursuing infrastructure returns and national decarbonisation goals.